Stability studies of PtSn structured catalysts supported on thin layers of MAl2O4 (M: Mg or Zn) for paraffins dehydrogenation reactions

BALLARINI, ADRIANA D; ZGOLICZ, PATRICIA D.; DE MIGUEL, SERGIO R; BOCANEGRA, SONIA A.

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING

JOHN WILEY & SONS INC

Lugar: New York; Año: 2022

0008-4034

In order to determine the catalytic stability, PtSn structured catalysts supported on thin filmsof MgAl2O4 or ZnAl2O4 deposited on -Al2O3 spheres were studied through five reactionregenerationcycles in the n-butane dehydrogenation. Bimetallic catalysts show good catalyticstability along the five reaction-regeneration cycles, much higher than that of thecorresponding monometallic catalysts. Among the different synthesized catalysts, thePtSn/Sp-Zn-CN catalyst showed the best catalytic behaviour, showing very good values ofyields to butenes and excellent catalytic stability along the cycles, even better than the one ofa structured commercial catalyst used industrially for dehydrogenation of paraffins. Thecharacterization results by Temperature Programmed Reduction and X-ray PhotoelectronSpectroscopy showed some modifications in the metallic phase of the catalysts after thecycles, mainly in the Sn/Pt surface ratios, in segregation effects in some catalysts and in theproportion of zerovalent tin in relation to oxidized Sn species. However, the TEM results areconclusive in the sense that, after the cycles, the bimetallic catalysts maintained a very highproportion of particles with sizes between 1 and 2 nm, and therefore, preserved a highmetallic dispersion. Despite some modifications found in the metallic phases during the reaction-regeneration cycles, the bimetallic catalysts showed a very good stability of theircatalytic properties along the cycles, even higher than that of a commercial catalyst.